This invention relates generally to shock absorption mechanisms for reducing impact or shock damage to disk drives.
Generally, a hard disk drive performs the function of recording and reproducing information stored magnetically on a spinning disk. Such drives typically include a disk assembly and an actuator assembly. The disk assembly often includes at least one magnetic disk coupled to a hub that is turned by a motor, and the actuator assembly typically includes an actuator arm supporting components on a one end for reading and writing data to and from the magnetic disk, and coupled to a motor for enabling movement of the actuator arm at the other end.
The ability of a disk drive system""s ability to withstand both internal and external shock and vibration while in operation has become increasingly important as the portability of computer systems increases. A typical external shock is one produced by the movement of the computer while the disk drive is in operation. A typical internal shock is one generated by the motion of the magnetic heads and other internal components during positioning operations. Undesirable levels of vibration may cause read/write errors, and may also delay the transfer of data because the data cannot be confidently transferred until the amplitude of vibration has substantially decayed. In addition to shifting the magnetic heads off track, certain external shocks could damage the disk drive assembly.
To prevent damage to the disk drive assembly, a number of shock absorption mechanisms have been used. Typical shock absorption mechanisms include shock-mounts supporting the disk drive assembly. The shock mounts are normally made of rubber, having a predetermined stiffness. However, such shock absorbing systems typically do not adequately address internal sources of shock. Furthermore, the disk-spindle assembly in the disk drive and actuator assembly may vibrate in different phase, which may cause the magnetic head contacting the surface of the disk, which may damage the surface of the disk.
What is needed is an improved disk drive assembly that reduces damage between the magnetic head and storage media caused by internal and external shocks, and that isolates the hub and the actuator so that they preferably vibrate in the same phase after a shock or impact.
Accordingly, the present invention is a shock absorption mechanism for reducing the damage experienced by disk drives, including damage caused by the magnetic head contacting the surface of the disk, resulting from impact or shock forces experienced by the disk drive. In general, the invention is a means for partially isolating a disk assembly and a related actuator assembly from other parts of the disk drive. In the preferred embodiment the shock absorption mechanism isolates the disk assembly and the actuator assembly from the outer frame of a housing containing the disk assembly and the actuator assembly by establishing a shock energy dissipation and absorption region between a pair of isolation plates and other parts of the disk drive. In the preferred embodiment, a bottom isolation plate is defined in a bottom wall of the housing by a series of apertures extending through the bottom wall of the housing. The top isolation plate is defined in a top wall of the housing by a series of apertures extending through the top wall of the housing. Thus, the top isolation plate and the bottom isolation plate are only connected to the rest of the housing by a series of bridges between the apertures cut in the top and bottom housing walls. The apertures are preferably slot shaped, but other shapes could be used. The shape of the isolation plates defined by the array of apertures may be configured as desired. The disk assembly and the actuator assembly extend between the top and bottom isolation plates. The isolation of the disk assembly and actuator assembly together between the top and bottom isolation plates may allow the disk assembly and the actuator assembly to oscillate in phase when subject to internal shock. The apertures are preferably covered and/or filled with a vibration dampening material that reduces vibration energy by absorbing kinetic energy and releasing the energy as heat.